java - 使用比较器对字符串列表进行排序

Question

我有-

import java.util.*;

public class TestCompare {

    List<String> list = Arrays.asList("10", "1", "20", "11", "21", "12");
    Comparator<String> cmp = new Comparator<String>() {
        public int compare(String o1, String o2) {
            return Integer.valueOf(o1).compareTo(Integer.valueOf(o2));
        }
    };
    Collections.sort(list, cmp);
}

在 Collections.sort(list, cmp); 有一个错误 - token "(", delete this token 的语法错误。这个语法有什么问题？

Answer 1

你不能直接在类中有代码，它应该在像main这样的方法中:

public class TestCompare {
    public static void main() {
      List<String> list = Arrays.asList("10", "1", "20", "11", "21", "12");
      Comparator<String> cmp = new Comparator<String>() {
      public int compare(String o1, String o2) {
        return Integer.valueOf(o1).compareTo(Integer.valueOf(o2));
      }
      };
      Collections.sort(list, cmp);
    }
}